Magnetic core matrix



June 23, 1964 E. J. sMURA MAGNETIC CORE MATRIX 2 Sheets-Sheet 1 FiledJuly 18, 1960 Mmmmmmmm FIG.

/NVENTOR EDWIN J. SMURA 42 FIG. 2 21x MW B .m1 E0. DN 0 N A AT TOR/VE YJune 23, 1964 E. J. sMURA 3,138,786

MAGNETIC CORE MATRIX Filed July 18, 1960 2 Sheets-Sheet 2 ANODE 1 TUBEIX Fla 5 United States Patent O 3,138,786 MAGNETIC CORE MATRIX Edwin li.Smura, Apalachin, NSY., assigner to International Business MachinesCorporation, New York, NX., a corporation of New York Filed July 18,1960, Ser. No. 43,385 8 Claims. (Cl. 340-174? This invention relates toan information handling matrix comprising binary elements and, moreparticularly, to a matrix in which the currents flowing in the drivelines of the matrix are combined; the combined current being channeledto energize a particular element.

Binary elements such as magnetic cores and ferroelectrie capacitors arewidely usedI in information handling matrices since they exhibit twostable states; remnant iiux states or polarization states, respectively.In a number of applications, the binary elements are arranged to have atleast a pair of current carrying or drive lines coupling current energythereto. Coincident currents in the drive lines are employed forselection and energization of particular elements of the matrix.However, the problem of driving and switching binary elements,especially magnetic cores, in matrices has remained complex. In general,it is desirable to drive or switch the binary elements with a relativelylarge current in order that the switching time be decreased.Consequently, when it has heretofore been attempted to employ cathoderay tubes as the driving means for matrices, serious limitations in theamplitude of the current available to drive the matrices have becomeapparent.

It is a principal c-bject of my invention to provide a matrix of binaryelements in which an element is energized to change its stable state bythe sum of the currents flowing in the matrix drive lines.

It is another object of my invention to provide a binary element matrixadaptable to be driven by sources of low amplitude current.

It is still another object of my invention to provide a binary elementmatrix adaptable to be driven by cathode ray tubes.

In one preferred embodiment, the invention provides a matrix comprisinga plurality of cores driven by cathode ray tubes. Each cathode ray tubeincludes a plurality of discrete anode tabs; each of the tabs istransformer coupled to respective drive lines of the matrix. The matrixincludes two groups of drive lines; each group of lines is connected toa respective common lead and each core has one line in each group beingwound, that is, passing therethrough. To select a core, the cathode raytubes are energized to provide a current through coupling transformersto all the drive lines except the two lines passing through the desiredselected core. In each group of lines, current will ow through the drivelines to the common line whence the currents are combined, and thecombined current flows through the drive line passing through theselected core; the combined currents are dissipated in line impedancematching resistors connected across a winding of the respective couplingtransformer.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings.

In the drawings:

FIG. l is a schematic diagram of a matrix array in accordance with theinvention;

FIG. 2 is a schematic diagram of a circuit for coupling current to thedrive lines; and,

FIG. 3 is a schematic diagram of a second matrix array in accordancewith the invention.

3,138,786 Patented .lune 23, 1964 ice FIG. 1 shows a matrix plane 11according to the invention. A relatively simplified form of a singleplane matrix is shown for purposes of facilitating the explanation ofthe operation of the invention. Matrix 11 comprises a total of 64 binaryelements; in this case, magnetic cores, arranged in a plane formed witheight rows and columns, with eight cores in each row and in each column.Collectively, the cores are designated by the numeral 13; the symbol Xdesignates the rows of the matrix; the symbol Y designates the columnsof the matrix. A first group of drive lines designated individually as21X-28X are wound to pass through the respective rows of cores and areconnected to a common line 29. Likewise, a second group of drive linesdesignated individually as 31Y-38Y are wound to pass through therespective columns of cores and are connected to a common line 39. Thus,in matrix 11, each of the cores 13 has two intersecting drive linespassing therethrough; that is, a core is positioned at the intersectionof each two drive lines and each line is wound to have one turn on thecore. Drive lines ZIK-28X, as well as lines 31Y-38Y, are each connectedto the secondary winding of a transformer, the primary of which isconnected to an anode of a cathode ray tube.

The cathode ray tubes employed for driving the matrix 11 are preferablyof the type shown in Patent Number 3,092,746 of E. I. Smura for CathodeRay Tube for Processing Digital Data, issued lune 4, 1963, and assignedto the same assignee as the present invention. For purposes of thisdescription, it will be appreciated that each of the cathode ray tubeshas a plurality of electron beamreceiving anode tabs and the electronbeam in each tube is controlled such that it impinges on only one of theanodes of a tube at a given instant. More specifically, in oneembodiment, each cathode ray tube has a total of 32 discrete anode tabs;16 of the tabs being used for writing and 16 of the tabs being used forreading, as will be described hereinbelow. As noted above, for ease inexplaining the concept of the invention, only a relatively small matrixplane is shown utilizing only two anodes in each of 16 cathode raytubes. Obviously, the plane shown can be expanded to include 128 drivelines in the X group and 128 lines in the Y group.

The tubes designated 1X-SX are connected effectively in parallel suchthat the electron beam is connected to impinge on the same anode of eachtube at a given instant. The anode tabs numbered 1 and 2 in tubes lX-Xare transformer coupled to energize drive lines 21X-28X, respectively.Likewise, cathode ray tubes lY-SY are connected in parallel such thatthe electron beam is caused to impinge on the same anode on each tube ata given instant. Anode tabs numbered 1 and 2 of tubes lY-SY aretransformer coupled to energize drive lines 31Y-38Y, respectively.

Since cathode ray tubes lX-SX and 1Y-8Y are all similar and operate in asimilar manner, and since the transformers associated with each tube aresimilar and operate in a similar manner, an explanation of one tube andthe associated transformer is thus deemed sutlicient to theunderstanding of the operation of my invention. Particular referencewill thus be made to cathode ray tube 1X and associated transformer 40coupled to drive line 21X.

The structure of transformer 40 is shown in more detail in FIG. 2.Transformer 4i) comprises a primary winding 41, a secondary winding 42and a tertiary winding 43. Magnetic material 40a having no sharplydefined remanant flux state inductively couples the primary winding 41to the secondary winding 42; and magnetic switching material having twostable remanant iiux states, such as a magnetic or ferrite core Mib,couples the secondary winding 42 to the tertiary winding 43. Primarywinding 41 has one terminal connected to anode tab number l in tube 1X,and its other terminal connected to anode tab number 2 of tube 1X; themidpoint of winding 41 is grounded. The upper half of winding 41; thatis, the portion extending from anode tab number 1 to ground, is wound ina first direction, say, counterclockwise, around transformer material40a; the lower half of winding 41 which extends from ground to anode tabnumber 2 is wound in the opposite or clockwise direction aroundtransformer material 40a. Secondary winding 42 has one terminalconnected to ground and the other terminal connected to drive line 21X.Tertiary winding 43 has a resistor 44 connected thereacross. Resistor 44is selected to match the characteristic impedance of line 21X and thusprevents any energy received through 21X from being reflected back downthe line for purposes which will be evident hereinbelow. For currentless than a given amplitude, as will be explained hereinbelow, themagnetic core 40.5 provides zero coupling between the secondary winding42 and tertiary winding 43 such that the tertiary winding does notaffect the operation of the circuit. For currents above a givenamplitude, the core 4012 will switch or change stable states and therebycouple energy to the tertiary winding, which energy is dissipated byresistor 44.

The upper half of winding 41 is utilized as the write line and the lowerhalf of winding 41 is utilized as the read line. The odd-numbered anodetabs in the cathode ray tubes are used to write and the even-numberedanode tabs are used to read. In one embodiment, each tube has 32 anodetabs, with 16 tabs used in reading and 16 tabs used in writing. As isknown, the write and read operations in the matrix are essentiallysimilar with the binary element being driven to one stable state duringthe writing operation and being driven to the other stable state duringthe reading operation.

As noted above, tubes lX-SX comprising the X drive group have theirdeflection plates electrically connected in parallel, thus the electronbeam is directed to impinge on the same respective anode in each tube ata given instant; that is, during each selection period. Likewise, tubeslY-SY have their deflection plates electrically connected in parallelsuch that the electron beam is directed to impinge on the samerespective anode in each tube during each selection period.

The tubes 1X-8X and lY-SY are controlled to be turned on or off; thatis, the tubes are controlled to have an electron beam being emitted fromthe respective cathode of a tube and impinging on one of the anode tabs,or the electron beam is not being emitted; that is, the beam is cut off.

The writing operation of the matrix is as follows. Assume that it isdesired to energize the core designated as 13Q in matrix 1l. Assumeinitially that core l3Q is in an initially neutral state. Tubes lX-4Xand X-SX, that is, all the tubes in the X group except tube 5X, will beon, or conducting. Likewise, tubes 1Y-4Y and Y-SY, that is, all thetubes in the Y group except tube SY, will be on. All the tubes which areturned on will be addressed such that the electron beam is directed toimpinge on anode number 1. Thus, in tube 1X, for example, a current Iwill be caused to flow in transformer 4t) from anode number 1 throughthe upper part of primary winding 41 to ground reference. A current NI,indicated by the solid arrow, will flow in the secondary winding 42 dueto transformer action; N being the current transfer ratio of thetransformer. The current path is traceable from ground through secondarywinding 42, drive line 21X to the common line 29 and to point A.Likewise, in each of the tubes which are turned on in the X and Y drivegroups, the current impinging on anode number 1 will cause a current Ito flow in the respective primary winding inducing a current NI in thesecondary winding which flows in the direction shown by the solid arrowsin the respective drive line. Note, in this case, that all the X drivelines except drive line 25X will be energized by the respectivetransformer to have current flowing therein. The current in drive lines21X-24X and 26X-28X will flow toward and be summed in common line 29; inthis particular case, at junction point A. A total current of 7 NI willthus be flowing into junction A. From Kirchhoffs Law, it will beappreciated that the sum of all the current flowing into junction A mustequal the sum of the current flowing away from junction A. Therefore,all the currents flowing into junction A will be summed and a totalcurrent 7 NI will flow away from junction A, through drive line 25X andthe secondary winding 51 of the transformer 50 associated with tube 5Xto ground. The total current 7 NI in the secondary winding 51 will causethe core material of transformer S0 to switch magnetic states and causetertiary winding 52 to couple a current to load resistor 50K. Sinceresistor SOR is matched to the characteristic impedance of line 25X, itwill dissipate all the energy flowing in line 25X and no current will bereflected back.

The operation is similar for the Y group of drive lines. All the Y drivelines except drive line 25Y will be energized by the respectivetransformer to have current flowing therein. A current NI, shown by thesolid arrows, will flow in each of lines 3lY-34Y and 36Y-38Y toward acommon line 39 and junction B. At junction B, the currents will besummed and a total current 7 NI, shown by the solid arrow, will flowdown drive line 35Y through the secondary winding 61 of the transformer60 associated with tube SY. The total current 7 NI in the secondarywinding 61 will cause the core material of transformer 6G to switchmagnetic states and cause tertiary winding 62 to couple current 7 NI t0resistor 60R, where the current is dissipated.

The current flow through the X and Y groups of drive lines is arrangedto be concurrent; therefore, it will be obvious that a total current of14 NI will be passing through the desired core 13Q. The The totalcurrent flowing through core 13Q is sufficient to energize core BQ andcause it to shift from one to the other of its stable states.

As will be appreciated, the reading operation is similar to the writingoperation. In this case, the desired tubes are addressed, such that theelectron beam is caused to impinge on anode number 2 in each tube. Asabove, all the tubes except tubes 5X and SY are turned on. Current willthus flow in the primary windings of all the transformers excepttransformers 5t) and 60 associated with tubes 5X and SY. Since theelectron beams are impinging on the anode number 2 in each tube, thecurrent flowing through the lower half of winding 41 will induce acurrent in the secondary winding which will flow in a relativelyopposite direction from that shown above for the Write operation; thatis, the current will be flowing through the drive lines in the directionshown by the dotted arrows. The theory of operation is as stated above,with the direction of the current flow being reversed. It can beconsidered that the total current 7 NI, shown by the dotted arrow,showing in the X group of drive lines, will flow from ground reference,through the secondary winding 51 of the transformer 50 and drive line25X to point A, and will divide into seven approximately equal currentswhich flow through each of the other drive lines in the X group andthrough the secondary windings of the respective transformers to ground.

The Y group of drive lines functions in a similar manner. The electronbeam is addressed to impinge on the second anode of each of the tubes inthe Y group. All the tubes in the Y group, except tube SY, are turned onor conducting. A current will be caused ,to flow in the direction shownby the dotted arrows through each of the Y drive lines. It can beconsidered that the total current 7 NI, shown by the dotted arrow,flowing in the Ygroup of drive lines, will flow from ground through thesecondary winding 61 of transformer 60 and drive line 25Y to point B andwill then divide into seven approximately equal currents which will flowthrough each of the other drive lines in the Y group and through thesecondary windings of the respective transformers to ground. Commonlines 29 and 39 thus provide a means of combining the currents in therespective X and Y groups of drive lines, and the matrix arrangementchannels or directs the combined current to flow through the drive linesassociated with the core to be selected.

The current ow through the X and Y groups of drive lines is arranged tobe concurrent; therefore, the total current 14 NI will be sufficient toenergize or switch core 13Q from the stable state to which it Wasenergized by the writing operation to its other stable state and thusprovide a reading operation.

A suitable sensing line 70 of any well-known type is wound through eachof the cores in series such that a writing or reading operation issensed when a selected core shifts from one to the other of its stablestates.

As noted above, the matrix plane shown is relatively small and may beonly a part of a larger plane. With the type and number of tubes shown,the matrix plane may be expanded to include 128 drive lines in each ofthe X and Y groups since each cathode ray utbe comprises 16 anode pairs;also, various combinations of dive lines in the two groups of lines thatmay be energized for selecting a particular element. Any number of tubesmay also be used and the number of drive lines is essentially unlimited.

It should also be understood that a number of separate matrix planes canbe employed; the drive lines in a plane can be connected to the drivelines in other planes, and the common line in which the currents aresummed can be in any one of the planes.

FIG. 3 shows an example of a larger matrix array according to theinvention. The principle of operation of the circuit of FIG. 3 is thesame as that described for FIGS. 1 and 2; therefore, a detaildescription of FIG. 3 is not considered necessary since the operation ofthe circuit of FIG. 3 can be understood by reference to Table I whichfollows this paragraph and which is essentially self-explanatory. In thecircuit of FIG. 3, four tubes are used in each of the X and Y groups andeight anodes in each tube are coupled to the matrix. During eachselection period, three of the four tubes in each of the X and Y groupsare turned on, causing current to flow in three of the four drive linesof each of the X and Y groups respectively. As before, the tubes in eachgroup are connected in parallel such that the electron beam is caused toimpinge on the same respective anode tab in each of the tubes in a groupduring a given selection period. However, since two groups of tubes witha plurality of anode tabs in each tube are utilized, variouscombinations of lines can be energized. For example, as seen from thetable, the electron beams can be addressed to impinge on anode number 1in the X group of tubes and the electron beams can be addressed toimpinge on the anode number 1 in the Y group of tubes; or, as indicatedon the lower half of the graph, the electron beam can be caused toimpinge on anode tab number 3 of the X group and anode tab number 1 inthe Y group. Any number of such combinations can obviously be obtained.As in FIG. 1, current will be caused to ow in those drive linesconnected to the anodes on which the electron beam is impinging. Forexample, if tubes 1, 2 and 3 in the X group are turned on and theelectron beam impinges on anode tabs number 1, currents 11X, 15X and 19Xwill flow in lines 1X, 5X and 9X, respectively; likewise, when tubes 1,2 and 3 in the Y group are turned on and the electron beam impinges onanode tabs number 1, currents IlY, I5Y and I9Y will flow in lines 1Y, SYand 9Y, respectively. By turning on various combinations of tubes andaddressing the electron beam to irnpinge on various anode tabs,different cores in the matrix may be energized, as indicated in thetable.

Table 1 X GROUP TUBES, BEAM TO ANODE #l-Y GROUP TUBES, BEAM TO ANODE #lGROUP TUBES, BEAM TO ANODE #S-Y GROUP TUBES BEAM TO ANODE #l While theinvention has been particularly shown and described with reference topreferred embodiments thereof, it will be understood by those skilled inthe art that the foregoing and other changes in form and details may bemade therein without departing from the spirit and scope of theinvention.

What is claimed is:

l. A matrix comprising a plurality of binary elements, row and columndrive lines connected to a plurality of current sources for couplingcurrent energy from said plurality of current sources to said elements,means including a common connection between said drive lines forcombining the current flowing in said drive lines, and means including acommon connection between said sources for channeling the combinedcurrent to ilow through selected ones of said row and column drive linesto energize a selected element.

2. A matrix comprising a plurality of binary elements, at least irst andsecond groups of drive lines having a separate current sources connectedto each line for coupling current energy from the plurality of currentsources to said elements, means associated with each group of lines forcombining the current tlowing in said drive lines, and means including acommon connection between the sources of each group for channeling thecombined current in each group of lines to ow through a selected one ofthe lines in each group to energize a selected element.

3. An information handling matrix comprising a plurality of binaryelements arranged in rows and columns, at least irst and second groupsof current carrying drive lines associated with the rows and columns ofelements respectively, each element being energizable by at least one ofthe drive lines in each group, a first common junction for said firstgroup of lines, and a second common junction for said second group oflines, means for connecting the lines of each group to separate sources,including a common connection between the sources of each group,whereby, to select an element, all the lines in the matrix except thoselines associated with the selected element receive current energy withtheir respective sources, the received current being combined at saidjunctions and flowing through the lines which are associated with theselected element, and the total of the combined currents flowing throughthe lines associated with the selected element energizes the element.

4. An information handling matrix comprising a plurality of binaryelements arranged in rows and columns, at least first and second groupsof current carrying drive lines one group being associated with theelements of the rows and the other with the elements of the columns,each element being energizable by or associated with at least one of thedrive lines in each group, a first common junction for said first groupof lines, and a second common junction for said second group of lines,transformer source means individual to each line, and circuit meansconnecting the source means of each group, whereby, in selecting anelement, all the lines in the matrix except those lines associated withthe selected element receive current energy with their respective sourcemeans, the received current combining at said junctions and flowingthrough the lines which are associated with the selected element, andthe total of said combined currents flowing back through the lines insaid first and second groups associated with the selected element,causing said selected element to be energized.

5. A matrix comprising a plurality of binary elements having two stablestates, first and second groups of drive lines for energizing saidelements, said first andrsecond groups of lines being connected to firstand second common junctions respectively, each element being energizableby an associated drive line of each group, a plurality of sourcesselectively controllable to develop or not develop current energy, andmeans including a saturable transformer for coupling each of saidsources to a respective drive line for selecting a particular element inthe matrix, said transformer of each group having a common connectionand said sources being controllable to provide energy in one directionto all of said drive lines except the two drive lines associated withthe particular element, the current flowing in said first and secondgroup of drive lines being combined at said first and second junctionsrespectively, said combined current in each group flowing in theopposite direction through the drive lines associated with the elementto be selected, whereby the total of said summed currents causes saidselected element to be energized to one of its stable states.

6. A matrix comprising a plurality of binary elements having two stablestates, first and second groups of drive lines for energizing saidelements, said first and second groups of lines being connected to firstand second cornmon junctions respectively, each element beingenergizable by an associated drive line in said first group and anassociated drive line in said second group, a plurality of currentsources selectively controllable to provide or not provide currentenergy, and means including a saturable core transformer having aplurality of windings including primary and secondary windings forcoupling each of said sources to a respective drive line, for selectinga particular element all of said sources except the sources coupled tothe two drive lines associated with the selected element beingcontrolled to provide current energy to their respective lines, thecurrent flowing in said first group of drive lines being combined atsaid first junction and said combined current flowing through the driveline in said first group associated with said selected element, thecurrent flowing in said second group of drive lines being combined atsaid second junction and said combined current flowing through the driveline in said second group associated with said selected element, wherebythe total of said combined currents causes said selected element to beenergized to one of its stable states, and means including another oneof said winding connected to a load matching impedance for coupling saidimpedance to the other windings so long as the core is not saturated.

7. A matrix comprising a plurality of binary elements each having twostable states, a plurality of drive lines; at least two drive linesbeing arranged to energize each of said elements; current coupling meanscomprising a transformer having a first core with no defined stablestates, a second core having two stable states, a primary winding and asecondary winding wound on both of said cores, and a tertiary windingwound on said second core; a line matching resistor connected acrosssaid tertiary winding; a plurality of sources of current energy; theprimary winding of each of said transformers being connected to arespective source; the secondary winding of each transformer beingconnected to one end of a respective drive line, the other end of eachof said drive lines being connected to a common junction; each of saidsources of current being controllable for energizing the respectivetransformer for developing current flow in the respective drive line; abinary element being selected by developing current flow in all saiddrive lines except the drive lines associated with the selected element,said current in said drive lines being combined at a common junction andsaid combined current flowing in the drive lines associated with theselected element to energize said element to one of its stable states,and said combined current energizing the second core of the transformercoupled to the line associated with the selected element to change fromone to the other of its stable states, thereby to energize said tertiarywinding and cause the combined current to be dissipated in said linematching resistor.

8. A matrix comprising a plurality of binary elements each having twostable states; first and second groups of current carrying drive lines,each element being energizable by one of the drive lines in each group;each drive line in said first groups having one terminal connected to afirst common junction, each line in said second group having oneterminal connected to a second common junction; a plurality of currentcoupling means each comprising a transformer having a first core with nodefined stable state, a second core having two stable states, a primarywinding, a secondary winding, a tertiary winding, said primary andsecondary windings being wound on both of said cores, said tertiarywinding being wound only on said second core, and a line matchingimpedance being connected across said tertiary winding; one terminal ofeach said secondary winding being connected to ground and the otherterminal being connected to the other terminal of a respective driveline; first and second groups of sources of current each individuallycontrollable to provide or not provide current; each source connectedfor providing current to the primary winding of a respectivetransformer; current flow in a primary winding source causing a currentto be induced in the associated secondary winding and consequent currentflow in the associated drive line; the magnitude of the current providedby each source to the respective primary winding being insufficient toshift the state of the respective second core; whereby no current energyis coupled to the respective tertiary winding; for selecting aparticular element in said matrix all said sources except those sourcescoupling current energy to the selected element being activated toprovide current energy to the respective drive lines; the currentsflowing in each line of said first group of drive lines being combinedat said first junction and flowing through the drive line in said firstgroup which energizes said selected element; the currents flowing ineach line of said second 9 10 group of drive lines being combined atsaid second juncand be dissipated in the associated line matchingimpedtion and owing through the drive line in said second ance. groupwhich energizes said selected element; the total of References Cited inthe tile of this patent said combined currents energizing said elementto shift UNITED STATES PATENTS its stable state; and each of saidcombined currents being 5 of Sufficient magnitude to shift the stablestate of the secilglan "b'zg ond core 1n the respective transformerwhereby current 0723392 Kluck Jan. 8 1963 energy is coupled to thetertiary winding to ow through

8. A MATRIX COMPRISING A PLURALITY OF BINARY ELEMENTS EACH HAVING TWOSTABLE STATES; FIRST AND SECOND GROUPS OF CURRENT CARRYING DRIVE LINES,EACH ELEMENT BEING ENERGIZABLE BY ONE OF THE DRIVE LINES IN EACH GROUP;EACH DRIVE LINE IN SAID FIRST GROUPS HAVING ONE TERMINAL CONNECTED TO AFIRST COMMON JUNCTION, EACH LINE IN SAID SECOND GROUP HAVING ONETERMINAL CONNECTED TO A SECOND COMMON JUNCTION; A PLURALITY OF CURRENTCOUPLING MEANS EACH COMPRISING A TRANSFORMER HAVING A FIRST CORE WITH NODEFINED STABLE STATE, A SECOND CORE HAVING TWO STABLE STATES, A PRIMARYWINDING, A SECONDARY WINDING, A TERTIARY WINDING, SAID PRIMARY ANDSECONDARY WINDINGS BEING WOUND ON BOTH OF SAID CORES, SAID TERTIARYWINDING BEING WOUND ONLY ON SAID SECOND CORE, AND A LINE MATCHINGIMPEDANCE BEING CONNECTED ACROSS SAID TERTIARY WINDING; ONE TERMINAL OFEACH SAID SECONDARY WINDING BEING CONNECTED TO GROUND AND THE OTHERTERMINAL BEING CONNECTED TO THE OTHER TERMINAL OF A RESPECTIVE DRIVELINE; FIRST AND SECOND GROUPS OF SOURCES OF CURRENT EACH INDIVIDUALLYCONTROLLABLE TO PROVIDE OR NOT PROVIDE CURRENT; EACH SOURCE CONNECTEDFOR PROVIDING CURRENT TO THE PRIMARY WINDING OF A RESPECTIVETRANSFORMER; CURRENT FLOW IN A PRIMARY WINDING SOURCE CAUSING A CURRENTTO BE INDUCED IN THE ASSOCIATED SECONDARY WINDING AND CONSEQUENT CURRENTFLOW IN THE ASSOCIATED DRIVE LINE; THE MAGNITUDE OF THE CURRENT PROVIDEDBY EACH SOURCE TO THE RESPECTIVE PRIMARY WINDING BEING INSUFFICIENT TOSHIFT THE STATE OF THE RESPECTIVE SECOND CORE; WHEREBY NO CURRENT ENERGYIS COUPLED TO THE RESPECTIVE TERTIARY WINDING; FOR SELECTING APARTICULAR ELEMENT IN SAID MATRIX ALL SAID SOURCES EXCEPT THOSE SOURCESCOUPLING CURRENT ENERGY TO THE SELECTED ELEMENT BEING ACTIVATED TOPROVIDE CURRENT ENERGY TO THE RESPECTIVE DRIVE LINES; THE CURRENTSFLOWING IN EACH LINE OF SAID FIRST GROUP OF DRIVE LINES BEING COMBINEDAT SAID FIRST JUNCTION AND FLOWING THROUGH THE DRIVE LINE IN SAID FIRSTGROUP WHICH ENERGIZES SAID SELECTED ELEMENT; THE CURRENTS FLOWING INEACH LINE OF SAID SECOND GROUP OF DRIVE LINES BEING COMBINED AT SAIDSECOND JUNCTION AND FLOWING THROUGH THE DRIVE LINE IN SAID SECOND GROUPWHICH ENERGIZES SAID SELECTED ELEMENT; THE TOTAL OF SAID COMBINEDCURRENTS ENERGIZING SAID ELEMENT TO SHIFT ITS STABLE STATE; AND EACH OFSAID COMBINED CURRENTS BEING OF SUFFICIENT MAGNITUDE TO SHIFT THE STABLESTATE OF THE SECOND CORE IN THE RESPECTIVE TRANSFORMER WHEREBY CURRENTENERGY IS COUPLED TO THE TERTIARY WINDING TO FLOW THROUGH AND BEDISSIPATED IN THE ASSOCIATED LINE MATCHING IMPEDANCE.